Finding the Third Proportional to 378.50 and 788.50

Step by Step Solution

1. Step 1: Write the proportion equation
   378.50 : 788.50 = 788.50 : x
2. Step 2: Convert to fraction form
   378.50/788.50 = 788.50/x
3. Step 3: Cross multiply
   378.50x = 788.50 × 788.50
4. Step 4: Simplify right side
   378.50x = 621,732.25
5. Step 5: Solve for x
   x = 621,732.25/378.50
6. Step 6: Final answer
   x = 1,642.62